Control Module Throttle Actuator Position Performance (GM)
What does P1515 mean?
The P1515 code means the vehicle's onboard diagnostic system has detected: Control Module Throttle Actuator Position Performance (GM). This is a moderate severity code.
Common Symptoms
- Reduced engine power warning
- Check Engine Light illuminated
- Throttle response delayed or limited
- Engine enters limp mode limiting speed
- Erratic idle speed
Probable Causes (Ranked by Likelihood)
- Dirty throttle body restricting plate movement Very High
- Faulty throttle position sensor High
- Worn throttle body motor High
- Wiring issue between ECM and throttle body Moderate
- Faulty accelerator pedal position sensor Low
Step-by-Step Diagnostic Procedure
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Clean the throttle body thoroughly with throttle body cleaner.
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Monitor both TPS sensors (TPS1 and TPS2) on a scan tool. They should move in opposite directions smoothly.
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Check the throttle body connector for corrosion or loose pins.
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Inspect wiring between the ECM and throttle body for damage.
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Perform a throttle body relearn after any service.
Frequently Asked Questions
Why do P1514 and P1515 often appear together?
Both codes relate to throttle body performance and are often caused by the same issue, typically carbon buildup. P1514 focuses on overall throttle body performance while P1515 specifically monitors the actuator position.
Can a dirty throttle body cause limp mode?
Yes. If carbon deposits prevent the throttle plate from moving to the position the ECM commands, the mismatch triggers a performance code and the ECM enters limp mode as a precaution.
Do I need a new throttle body or just cleaning?
Start with cleaning. The vast majority of P1515 codes on GM vehicles are resolved by cleaning and performing a relearn. Only replace the throttle body if cleaning does not resolve the issue or if the TPS sensors are faulty.